1. Field of the Invention
The present invention relates generally to heat exchangers for motor vehicles and, more specifically, to a flat turbulator for a tube and method of making same for a heat exchanger in a motor vehicle.
2. Description of the Related Art
It is known to provide a tube for a heat exchanger such as an oil cooler in a motor vehicle. The tube typically carries a first fluid medium in contact with its interior while a second fluid medium contacts its exterior. Typically, the first fluid medium is oil and the second fluid medium is air. Where a temperature difference exists between the first and second fluid mediums, heat will be transferred between the two via heat conductive walls of the tube.
It is also known to provide corrugated fins or ribs in the interior of the tube to increase the surface area of conductive material available for heat transfer to cause turbulence of the fluid carried in the interior of the tube and to increase the burst strength of the tube. One known method of making such a tube is to physically insert a corrugated fin into the generally flattened tube after the tube has been manufactured. This is an extremely difficult process since the corrugated fin to be inserted into the tube is extremely thin and subject to deformation during the insertion process.
It is also known to produce a corrugated fin or turbulator by a stamping process. An example of such a turbulator is disclosed in U.S. Pat. No. 5,560,425. In this patent, the turbulator is made by stamping in a direction parallel to the fluid flow or strip direction of the turbulator and has corrugations in a direction perpendicular to the direction of the flow of the fluid or strip direction.
Although the above turbulators have worked well, they suffer from the disadvantage that the stamping process does not have a high production through put. Another disadvantage of these turbulators is that the turbulators are inserted after the tube is made. Therefore, there is a need in the art to provide a tube with a flat turbulator and method of making same for a heat exchanger of a motor vehicle that overcomes these disadvantages.